distinctive feature

noun Linguistics.

a feature of the sound system of a language that serves as the crucial distinguishing mark between two phonemes, as the distinctive feature of voicing, which distinguishes b from p in English, or nasality, which distinguishes m from b and p.
any of a set of phonetic properties, as coronal, nasal, or strident, serving as a basic unit of phonological analysis by which the sounds that are significant in a language can be characterized and distinguished from one another.
a component or phonetic feature characterizing a phoneme.

Origin of distinctive feature

First recorded in 1925–30